How to check if the game is a fresh install or Update?

Unity Engine
1

I have a Unity 5 game that have a “lite” version with 25 free levels and “pro” paid version with 50 levels.

What I want to do is remove the lite version from the play store and have only the pro version, but make it free and have an in-app purchase to unlock the levels.

The problem I’m facing is how to check if the player already paid for the game through google play store when the game was a “Paid App”. So they don’t have to rebuy the game with an in-app purchase to play all 50 levels?

I was thinking about doing this:
Check if the player are updating the game:
if true: Unlock all 50 levels
false(making a fresh install): Lock the 25 last levels and require an in-app purchase to unlock the full game.

Is there a simple way to check this or does anyone have a better solution?

2

Well… the only thing I can think of is to update the existing app, and have it create a player pref for something like “isFullVersion” so that later when you roll out the combined version, if that is true, it must be a paid version, give them the levels.

Problem though is those who didn’t update would get lost… so you’d need a way for them to contact you, and for you to enable them manually if they were a paying customer.

If somebody has a better solution, avoid doing it that way.

In fact it’s bad advice lol, might be better off just creating a real file rather than playerprefs, something with more persistence. Can’t give you any better advice though sorry!